Hi Rob,
it depends on the nature of training you are planning to provide – ie the level of it and the audience.

If it is a general introduction, an overview, a company presentation, or even to prepare someone for the ITIL Foundation exam, then once you (and they) are satisfied with your understanding of ITIL and abilities in training, off you go ! There are no 'official' pre-requisites for a trainer at this level - as long as you don't present yourself or the material as being 'Accredited' that is and as long as you observe the rigorous (read 'expensive') copyright and licensing requirements of the official ITIL publications.

For any ITIL training leading to qualifications beyond Foundation level, students must attend an Accredited course. That requires the training provider, the materials and you the trainer/s to all be Accredited by an Examination Institute. So If your objective is something in this area, there are some quite reasonable quality hoops to jump through first and you will need time and some help with this - eg you will need to demonstrate knowledge of the subject (what ITIL certification do you have ?), relevant experience in your work history and an ability to 'train' so you will probably be expected to observe and then deliver the material under supervision - possibly a number of times - before you are allowed to go solo as an 'Accredited' trainer.

If you explain a little further where you are starting from and what is your objective, I may be able to give you some pointers – I am a freelance ITIL trainer myself.

As Alison says, you can deliver overview courses un-accredited, and it is possible to also deliver Foundation level, if students are going to sit the exam on-line. But I am concerned that you wish to become accredited but do not want to spend time on achieving that. Accredited means that you have been assessed and found to have the necessary knowledge, experience and training ability to help students to learn and pass the exams. It is only fair to the students that this is the case.
It is similar to the students who come on courses and are horrified that they need to actually learn the material if they want to pass the exam, rather than just being present in the classroom. I did have one student who sulkily asked "Do we actually have to learn this?" - I told him that that was only true if he wanted to get the qualification!
Accreditation means quality-assured - so of course it takes time and effort!_________________Liz Gallacher,
ITIL EXPERT
Accredited ITIL and ISO/IEC20000 Trainer and Consultant - Freelance

I have been teaching ITIL foundation for a year now and doing a great job. I am considering to teach higher levels of ITIL now So can you please advise who to contact exactly to become an Accredited trainer.

You need to apply to EXIN, ISEB or APMG. Their requirements may differ. For ISEB, you need get a Training Organisation to sponsor you and let you sit in/train under supervision a few courses. You also need Red Badge certification. For V3 you need to have passed each exam you teach._________________Liz Gallacher,
ITIL EXPERT
Accredited ITIL and ISO/IEC20000 Trainer and Consultant - Freelance